Key Virginia ADU Laws
Virginia ADU Laws
- No state rule in force today: each city, county and town decides in its own zoning ordinance whether ADUs are allowed, how big they may be and whether the owner must live on site.
- SB 531 (Acts of Assembly 2026, ch. 895), approved 13 April 2026, adds Va. Code § 15.2-2292.4, effective 1 July 2027: single-family zoning districts are deemed to include ADUs as a permitted accessory use, and a locality may not require anything beyond the section (subsection B).
- Permit and fee: an ADU permit from the locality, fee capped at $500 on top of building and inspection fees, to be issued when the ADU meets the section and local codes (subsection C).
- What a locality may still require (subsection D): a 30-day minimum lease, replacement of lost parking or dedicated ADU parking, a floor-area cap no lower than 350 sq ft (lots under 2,500 sq ft) or 500 sq ft, building, septic, flood and historic-district compliance, owner-occupancy of one unit only at application, the ADU within 500 ft of the house, no ADU on a lot that already has more than one dwelling, and no separate sale or subdivision.
- What it may not require (subsection E): rear or side setbacks, height, lot-size or coverage rules stricter than for the house or accessory structures; a restrictive covenant; street improvements; or any family relationship between occupants.
Who is exempt
- Nothing in § 15.2-2292.4 applies to a locality that adopted an ADU ordinance before 1 January 2026 (subsection I), and permits approved before 1 July 2027 are unaffected (subsection G). Arlington, Alexandria and other localities with older ADU ordinances therefore keep their own rules unless they choose to amend them.
What changed recently in Virginia
Gathered from the 2 cities below, with the bill or ordinance each one names. Statewide measures are listed once with the cities they reached, rather than repeated for each.
Statewide
- Virginia SB 531 (Acts of Assembly Ch. 895, approved April 13, 2026; effective July 1, 2027) adds Code §15.2-2292.4 requiring ADUs as a permitted accessory use in single-family districts with a $500 permit-fee cap and no family-relation or restrictive-covenant requirements - but subsection I exempts any locality that adopted an ADU ordinance before Jan 1, 2026, so Arlington's §12.9.2 rules (owner-occupancy, covenant, 750 sq ft cap) stay in force unless the County Board amends them. — cited by Alexandria, Arlington
City by city
- Arlington: Re-verified Sept 20, 2026 against the Arlington County Zoning Ordinance as codified June 13, 2026 (§12.9.2, §3.2.6, §14.3, §12.9.12), the county's Accessory Dwelling Permit page and the FY2027 fee schedules: the size, height, setback, parking and owner-occupancy rules are unchanged; the old page's permit-fee range ($2,800-$4,500) and 'impact fees $1,000-$1,800' were replaced with the published FY2027 figures (AD Permit $582; no impact fee); short-term rental corrected from 'not permitted' to 'allowed as an accessory homestay'.
- Arlington: Expanded Housing Option (EHO, §10.4): the Virginia Court of Appeals reversed the Circuit Court's 2024 ruling on Sept 5, 2025 and EHO permits reopened Oct 1, 2025; on May 19, 2026 the Virginia Supreme Court agreed to hear a narrow appeal about a developer's participation and did not halt EHO. EHO is a separate permit ($916) for duplexes through six-plexes and does not change the accessory-dwelling rules; §12.9.2 was never part of the lawsuit.
- Alexandria: 2026-09-20 re-verification: every standard re-traced to the adopted ordinance text (Text Amendment 2020-00007 implementing ordinance, final passage March 13, 2021) and the two later amendments below; the entry's old owner-occupancy, '70-100 days', 'ADU permit ~$75-100' and '$1,200-$2,000 impact fee' claims were wrong or unsourced and are corrected
- Alexandria: Short-term rental ordinance (Text Amendment 2024-00011, approved Feb 22, 2025, final passage March 15, 2025, effective Sept 1, 2025) repealed the 120-day cap on renting an ADU short-term (former Sec. 7-203(B)(7)) and added Sec. 7-1400: STR permit for rentals over 10 days a year, ADU occupancy capped at 3, no simultaneous STR of house and ADU
- Alexandria: Ord. No. 5593 (Text Amendment 2025-00003, approved May 17, 2025, final passage June 14, 2025) deleted the separate Planning & Zoning ADU permit (former Sec. 7-203(A)), the owner-occupancy-at-permit requirement (former (B)(6)) and the three-person occupancy cap in (B)(4); ADUs now go straight to a building permit
- Alexandria: FY2027 Planning & Zoning fee schedule effective July 1, 2026 (BAR residential new building $1,375 + $1.15/sq ft; addition or accessory structure of 250 sq ft or more $1,185 + $1.15/sq ft; BZA special exception $335); Code Administration building-permit rates are the FY26 schedule effective July 1, 2025
- Arlington: No accessory-dwelling amendment has been adopted since ZOA-2019-07 (adopted May 18, 2019, effective July 1, 2019), which created the current detached-AD standards; the 2026 amendments (ZOA-2026-01 Fort Myer Heights, -02 signs, -03 EV charging, adopted June 13, 2026) do not touch §12.9.2.
- Alexandria: Zoning for Housing (adopted Nov 28, 2023) only re-worded Sec. 7-203(B)(1) to 'single-unit, two-unit or townhouse'; the ADU standards come from the separate 2021 ordinance and are not part of the court challenge to the 2023 package (city reports 96 ADU approvals to Feb 20, 2026)
- Arlington: FY2027 Planning and Zoning and ISD fee schedules took effect July 1, 2026: AD Permit $582, DES parking survey $387, AD certificate of occupancy $520, residential building permit $1.70 per sq ft new construction, plus a 10% automation surcharge on all fees.
What the rules actually look like across Virginia
Statewide law sets a floor; the numbers that decide your project are local. Here is the spread across the 2 Virginia cities covered here, taken from each city's own ordinance rather than a state summary.
| Question | Across Virginia |
|---|
| Are ADUs permitted? | 2 of 2 permit them. |
| Detached size cap | Median 500 sq ft, from 350 to 500 sq ft across the 2 cities publishing a numeric cap. |
| Owner-occupancy | Required in 1 of 2. |
| Build cost | $150,000 to $350,000 depending on city and unit type. |
| Easiest and hardest here | Alexandria scores 7/10; Arlington scores 6/10. |
Recomputed whenever a city page changes, so this and the city pages below cannot disagree.
Virginia Cities ADU Comparison
| City | Max Size | Setbacks | Permit Fees | Build Cost | 1BR Rent | Score |
| Alexandria |
First floor of the detached accessory building may not exceed the greater of (a) one-third of the floor area of the principal dwelling's first floor or (b) 350 sq ft on lots of 2,500 sq ft or less / 500 sq ft on lots larger than 2,500 sq ft (Sec. 7-203(C)(1)). Only the first floor is capped; an upper floor is allowed within the 20 ft height limit. For this test, floor area includes space otherwise excluded by Sec. 2-145(A)(12)/(B)(14). |
Detached ADU building allowed in the required rear yard: at least 1 ft from the rear lot line including architectural features (unless the zone requires less); 3 ft if a wall with windows or doors faces that line; 2.5 ft for portions taller than 13.5 ft and under 16 ft; 5 ft for portions over 16 ft; and, outside the historic districts, 5 ft including overhang where a neighbor's window or door sill under 20 ft high sits within 3 ft of the shared line (Sec. 7-203(C)(3)). |
No separate ADU permit since June 2025 (a $135 ADU zoning-permit line remains in the FY2027 P&Z schedule; confirm). Building permit: new construction $0.75/sq ft plus $194 each electrical, plumbing, mechanical; alterations $0.30/sq ft ($95 min); plus 5% tech fee and state levy (FY26 schedule). |
$150,000-$350,000 |
$2,100-$3,150/mo |
7/10 |
| Arlington |
Gross floor area capped at the lesser of 750 sq ft or 35% of the combined floor area of house plus AD when the house is at least 1,000 sq ft; 500 sq ft or 45% when the house is under 1,000 sq ft (§12.9.2.A.2(e)). A detached accessory building approved after May 18, 2019 may hold an AD only if its footprint is 560 sq ft or less in R-5/R-6, 650 sq ft or less in the other R districts (§12.9.2.A.2(d)). GFA counts attic and basement space (§3.1.1). |
New detached AD building: 5 ft to the wall on interior lots; 10 ft to the eave on corner lots (§12.9.2.A.2(b)). The general §3.2.6 rule that no accessory building may be closer than 8 ft to any wall of the main dwelling also applies. |
AD Permit $582 plus $387 if a DES parking survey is needed (FY2027 Planning and Zoning fee schedule, effective July 1, 2026). Building permit $1.70 per sq ft for new construction/additions or $0.63 per sq ft for alterations, plus a 2% state levy and a 10% automation surcharge; CO for an AD $520. |
$150,000-$350,000 |
$2,100-$3,300/mo |
6/10 |
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